WASHINGTON (AFP) - US biotech firm Moderna said Friday (Feb 12) it was seeking clearance with regulators around the world to put 50 per cent more coronavirus vaccine into each of its vials as a way to quickly boost current supply levels.

The company issued a statement after The New York Times first reported the US Food and Drug Administration (FDA) had already cleared it to increase levels by 40 per cent.

"In order to better maximise resources as well as maximise opportunities to deliver more doses into each market faster, Moderna has proposed filling vials with up to 15 doses of vaccine versus the previous 10 doses," a spokesperson said in a statement to AFP.

The spokesperson added the company was engaging in discussions with the FDA and authorities in other countries, and the increased level of doses wouldn't require different vials to those currently in use.

"Any resulting change would be subject to final approval from the various regulatory authorities. Implementation of any such changes would be expected to be completed in approximately a two- to three-month period," it said.

Citing sources close to the matter, the Times reported that the FDA had agreed to Moderna using 14 doses per vial, compared to the previous 10.

This would require retooling of production lines that would take less than ten weeks, or before the end of April, the newspaper said.

"It would be a great step forward," Dr Moncef Slaoui, who was the chief scientific advisor for the federal vaccine development programme under former president Donald Trump, told the Times. "I think it will have an impact in the short term."

Some ten per cent of Americans have so far received at least one Covid vaccine dose, with Moderna accounting for just under half the number and Pfizer just over half.

The Biden administration announced Thursday it had reached a deal with both these companies to supply a total of 600 million doses of their two-shot courses by June, enough to cover 90 per cent of the US population.